1. Field of the Invention
This invention relates to a pouring plug which can be mounted on a paper container of a rectangular flat-top type or a gable-top type.
2. Description of the Prior Art
As a conventional pouring plug mounted on a paper container of a flat-top type or a gable-top type, there is known a pouring plug which comprises a tubular body adapted to be mounted on a container wall, a cap fitted over the tubular body, and a thrusting member vertically movable mounted within the tubular body to rupture the container wall. Examples of such pouring plugs are shown in Japanese published Utility Model application No. 58-37828 of Aug. 26, 1983, and in Japanese Laid-Open Utility Model applications Nos. 63-86022, of June 4, 1988, 64-35827 of Mar. 3, 1989, 64-35828 of Mar. 3, 1989 and 1-66324 of Apr. 27, 1989.
The aforementioned thrusting member is designed so that for opening a container, first, the cap is removed from the tubular body, and subsequently the thrusting member is firmly pushed by a finger or the like toward the container wall to rupture the container wall (see Japanese Utility Model Published application No. 58-37828). This opening operation is not easy. To overcome this drawback, improvements have been made in the cap and the thrusting member such that threads meshed with each other (see Utility Model Laid-Open application No. 63-86022), two inclined surfaces opposed to each other (see Utility Model Laid-Open application No. 1-66324), or an inclined surface and a projection (see Utility Model Laid-Open applications Nos. 64-35827 and 64-35828) are provided so that when the cap is rotated, the thrusting member is moved up and down to open the container.
The pouring plugs for containers heretofore known each comprise three members, a tubular body, a cap and a thrusting member, which are molded of plastic (for example, polyethylene) and assembled. This causes a problem in that manufacturing and assembling are inefficient.
That is, in the manufacture, three kinds of molds are required, and three steps are required in the molding operation.
The assembling operation also requires two steps, one for incorporating the thrusting member internally of the tubular body, and the other for fitting the cap over the tubular body.